Parrotia persica, Iron Tree: planting, pruning and care

Description and botany

Persian ironwood (Parrotia persica) belongs to family Hamamelidaceae and is now the only species of genus Parrotia although several varieties exist. This small tree or large bush is native to mixed forests of northern Iran and eastern Caucasus, hence species name “persica“, but is becoming rare in its natural habitat. It is called “iron tree” or “ironwood” because of hardness of its wood. Another of its (many) nicknames is “parrot tree” due to flamboyant colours of its foliage in autumn. This bush can also be found in older works under name Hamamelis persica.

Iron tree is a large bush or small tree measuring between 5 and 10 m high in cultivation, but it can reach up to 20 m in natural range. It has a stout trunk and a very spreading habit, often wider than tall (often nearly 10 metres wide). Branches of older specimens tend to arch to ground. Root system is extensive and tree even tends to produce suckers.

Bark is grey, but peels with age to reveal yellowish patches, somewhat like plane tree. Young shoots are green-brown with small hairs and buds are very dark purple, themselves slightly pubescent.

Deciduous foliage consists of ovate leaves about 8 cm long and glossy green in spring and summer (reddish at bud burst period) but becomes progressively very colourful in autumn with colours appearing simultaneously: green, yellow, orange and crimson to purple. Upper half of leaf margin bears rounded teeth and veins are prominent, somewhat reminiscent of beech leaf. It is therefore also nicknamed “Persian beech“.

Flowers are hermaphrodite, small and petal-less, composed of scarlet stamens surrounded by brown bracts. They appear directly on branches at end of winter (late February–early March) just before leaf emergence. Although inconspicuous, flowers are very melliferous and provide an excellent food source for early foragers emerging from winter. Fruit resulting from fertilization somewhat resembles a walnut and consists of a woolly capsule with four chambers. Seeds are light brown.

Parrotia persica : flowering, spring foliage then autumn foliage, beautiful bark

Parrotia reaches sexual ripeness at around ten years of age. It is a relatively slow-growing tree, gaining only about 30 cm per year, but can easily live for two hundred years.

Please note : only one species remains in genus Parrotia. Formerly it contained others such as Parrotia jacquemontiana now Parrotiopsis jacquemontiana and Parrotia subaequalis now Shaniodendron subaequalis.

Our favourite varieties

Parrotia persica - Persian Ironwood

Type species. Parrotia persica is a small deciduous tree that puts on magnificent autumn colours, blending green, yellow, orange, red and purple. Its discreet spring flowering is very melliferous. In winter it retains a strong presence when it reveals its beautifully peeling bark.

• Flowering time March to May
• Height at maturity 8 m

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Parrotia persica Vanessa - Persian Ironwood

Parrotia persica 'Vanessa' is an older horticultural selection still much appreciated for its almost columnar habit, in any case much narrower than the type species. This makes it particularly valuable in small gardens while retaining the qualities of the Parrotia type, notably incredible autumn colours.

• Flowering time March to May
• Height at maturity 6,50 m

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Parrotia persica Persian Spire - Persian Ironwood

Parrotia persica Persian Spire® is a brand new variety with a narrow habit and reduced vigour. Its foliage is remarkably colourful from spring to autumn, showing purple leaves at bud burst period, turning in summer to glossy green widely marginate with violet before the autumn blaze of yellow, orange and red. Unobtrusive, it will fit into any garden, even the smallest, or can be grown in a container.

• Flowering time March to May
• Height at maturity 7 m

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Parrotia persica Bella - Persian Ironwood

Parrotia persica Bella® is a variety of Persian ironwood that differs from the type species mainly by its narrower habit, making it easier to adopt in a medium-sized garden. Its narrow, semi-open, quite dense ovate crown will not exceed 4.50 m to 5 m in width.

• Flowering time March to May
• Height at maturity 10 m

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Sycoparrotia semidecidua Purple Haze

(x) Sycoparrotia semidecidua 'Purple Haze' is a hybrid between Parrotia persica and Sycopsis sinensis. It is a large bush reaching 3 to 4 m in height with a 4 to 6 m spread, whose foliage and habit display intermediate characteristics between those of its two parents.

• Flowering time March to May
• Height at maturity 4 m

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Planting Parrotia

Where to plant Parrotia?

Persian Parrotia is a very hardy tree, as it withstands frosts down to -25 °C. However, they dislike heat and are vulnerable to drought, although they become quite resilient once well established. Therefore avoid planting them south of the Loire, the climate being unsuitable.

This tree prefers rich, deep and acidic soils (autumn colours are then far more spectacular) but tolerates calcareous soil. It also needs the soil to remain cool but well drained. It can easily cope with heavy clay.

The ideal position is sunny but not scorching, or partial shade, sheltered from drying wind.

Allow plenty of space for this tree which tends to spread widely: at least 10 metres wide at maturity. Unless you choose a variety with a narrower habit such as ‘Vanessa’ or ‘Persian Spire’.

When to plant?

The best time to plant is autumn (November–December). Planting is also possible in early spring if soil is not frozen.

How to plant?

• Immerse the pot of your new Parrotia in a bucket of water for a few minutes to thoroughly re-wet the rootball
• Dig a hole twice as deep and twice as wide as the tree’s rootball
• Add a few handfuls of well-rotted compost to the bottom of the hole
• If your soil is heavy, add some sand or a little gravel to improve drainage
• Gently tease out the roots
• Place remaining rootball at bottom of hole, spreading out the roots
• Backfill the hole with the excavated soil, loosened beforehand
• Firm soil gently around tree with your hands (not with your feet!)
• Water the base with a 10-litre watering can to reduce risk of “air pockets” between roots and soil
• Apply a mulch to protect young tree from drought or plant some small groundcover plants at its base (creeping bugle, woodruff, Glechoma, Geranium macrorrhizum, …).

Maintenance, pruning and care

Care

Very little care is required for Persian ironwoods. Mulching is much appreciated, especially during the first years, to help retain coolness and moisture in summer.

During drought, check whether your Persian ironwood is suffering from a lack of water.

Pruning

No pruning is really necessary. If necessary, you can remove, just before growth resumes (February), fragile, dead branches or those that cross to preserve a harmonious, healthy habit.

Possible diseases

This bush or small tree does not suffer from any disease and is not attacked by any pests.

Propagation

Sowing

Sowing is difficult and lengthy; seeds take 18 months to germinate with a very low germination rate.

Layering

In fact, the tree layers naturally. Layering by trenching is an easy operation to carry out in March–April. Bend a few healthy flexible shoots down to soil. First, split the bark of these shoots for a few centimetres and to a thickness of about 2 mm. Bury your layers at the split and secure them with a stainless-steel “U”. Keep moist and wait at least two years before separating the layer from the parent plant. Remove it gently once it has rooted and then pot it up.

Propagation by cuttings

In June, try propagation by cuttings of semi-ripe shoots under a propagator. Take young shoots and cut the heel on a slant. Remove leaves, leaving only one to reduce evapotranspiration. The compost must be light; a 50% seed compost and 50% sand mix will be perfect. Keep moist but not waterlogged. Non-rooted cuttings do not “drink” and excess moisture will cause rot. First roots will appear by autumn, but it is better to wait until spring to repot. Wait at least until the following autumn, or better the following year, before planting out in ground.

Grafting

Parrotie is grafted onto Hammamelis: this is normal, they come from the same botanical family. This technique should be reserved for specialists (especially given price of Hammamelis…). Simply be aware that if you want to try nonetheless, the method known as the “cleft” graft is used and carried out in February.

Companion planting with Parrotia

Within a grove of foliage coloured in autumn

If you ask gardeners which is their favourite season, some will answer spring, but many will also say autumn. Autumn in garden and nature is indeed a magical season. If you love warm foliage colours of this season, why not create a grove of bushes renowned for their autumnal colours. Parrotia persica ‘Persian Spire’ takes little width, making it perfect to insert into a grove alongside Liquidambar styraciflua ‘Gum Ball’, a reduced-growth variety with multicoloured autumn foliage. A Forthergilla major will complete the picture while also enlivening spring with its charming flowering. If you are looking for another representative of family Hamamelidaceae to accompany Parrotia and Forthergilla, opt for a Hamamelis, such as this friendly Hamamelis vernalis ‘Amethyst’, with scarlet foliage in autumn followed by deep-pink winter flowering.

An example of a grove association: Parrotia persica ‘Persian Spire’, Liquidambar styraciflua ‘Gum Ball’ with incredible autumn foliage and Fothergilla major, to which you can add a Hamamelis with superb winter flowering such as ‘Amethyst’

Within a four-season informal hedge

Parrotia persica ‘Vanessa’ does not take much width, so it is ideal for a free hedge of bushes coloured by foliage and flowering. To keep interest throughout year, play on spring and summer flowering, autumnal foliage colouration and winter presence through colourful bark or distinctive habit, so Parrotia does not hog the limelight too often. Amelanchier spicata is perfect in a free hedge: attractive at flowering and during bud burst period in spring, and its foliage takes lovely tones in autumn. For summer, a simple but effective Buddleia davidii ‘Empire Blue’ is superb, flowering from July to September in long blue spikes. To complete the picture, plant to your heart’s content all dogwoods with decorative wood and foliage that come to hand. For example: Cornus alba ‘Aurea’ with golden foliage all season and bright red branches in winter, and Cornus sericea ‘Cardinal’ whose fresh green foliage gains reddish tones in autumn before giving way to red wood in winter.

An example of an association in a four-season hedge: Parrotia persica ‘Vanessa’ with lovely autumn colours, Amelanchier spicata which flowers in spring and also offers attractive autumn foliage, Buddleia davidii ‘Empire Blue’, Cornus alba ‘Aurea’ with golden foliage all season and Cornus sericea ‘Cardinal’ valued for its autumn colours and red stems in winter

Alone at the centre of a short grass meadow

Species type Parrotia persica takes some width over time (10 metres!), but it is also a very beautiful small tree to grow on its own, allowing it to reach its full stature. Standing proudly at the centre of an open area of your garden, it will quickly become a focal point that will lift hearts in autumn when it dresses itself in gold and flame. In addition, it will provide welcome shade for many attractive plants. If soil is sufficiently acid, why not try embellishing its base with heathers, azaleas or Pieris that will thrive in the shade of this fine tree.

→ Discover other ideas for pairing with Parrotia in our advice sheet !

Did you know?

• Genus name Parrotia honours its discoverer, German naturalist F.W. Parrot.
• It is a melliferous plant that attracts pollinators at a crucial time of year: the end of winter and the very start of spring.
• Parrotia persica was only introduced to Europe in 1841.
• Its vernacular name, iron tree, comes from its exceptionally hard wood.
• Parrotia wood has been used to make tools for more than 2,000 years.